The present invention relates to an artillery missile which, for firing on a ballistic trajectory towards a predetermined target, can be fired from a barrel weapon, and which can be guided on the trajectory towards the target. It is particularly characteristic of the missile according to the invention that it has been imparted, over and above the maximum range with regard to its own launching speed, an extended range by means of good gliding characteristics which can be brought into play on the trajectory and are put into effect after or immediately before the missile reaches its summit of trajectory.
The present invention therefore means that we have succeeded in combining in one and the same artillery missile a number of characteristics which are apparently difficult to combine with one another, namely that the missile can in the first place be fired from a barrel weapon of conventional type and will in the second place have good gliding characteristics during the descending phase of its ballistic trajectory, which, considering the great dead weight of each artillery missile in relation to its volume, requires large ballistic bearing surfaces which must moreover be effectively retractable so as not to interfere during the launching phase, and that the missile will in the third place be guidable at least during the descending phase of the ballistic trajectory, that is to say during the gliding flight of the missile. For guiding the missile, use is made according to the invention of what are known as canard fins which are arranged in the front part of the missile and can be extended after launching.
However, the use of canard fins for guiding artillery missiles has already been proposed previously in U.S. Pat. No. 4,438,893. In the missile described therein, however, the canard fins are mounted in a freely rotating missile nose. The main function of this construction is to make possible rotational stabilization of the missile on its trajectory at the same time as the missile nose and the fins, owing to the lateral resistance of the fins to the surrounding atmosphere, remain stationary on the trajectory and, by virtue of being inclined relative to the longitudinal axis of the missile, can influence the missile trajectory. It is therefore not lengthening the trajectory by gliding flight but only correction of the original ballistic trajectory of the missile which is involved in this context.
From DE-40 01 914, it is also known to produce launchable bodies which are airborne after launching and are provided with special bearing surfaces which are curved in towards the body in question during the launching phase and can be folded out or extended after launching. However, the type of bearing surface described there appears to be intended principally for sub-warheads to which it is desirable to impart a curved trajectory, because the bearing surfaces have been arranged in a zigzag shape one after another as far as those which form the right/left wing are concerned, and this design automatically produces a curved trajectory owing to the imbalance thus built in. The zigzag-shaped wing positioning moreover affords greater possibilities with regard to varying the shape of the wings, because they will then never collide in their retracted positions curved in towards the fuselage.
Finally, W098/43037 can be mentioned as an example of a stern-fin assembly for artillery missiles comprising a number of extendable fins which are covered during the launching phase by a protective cover and are extended as soon as this protective cover has been removed, but here, as in most other cases, it is a matter of a fin-stabilized shell without any form of advanced gliding characteristics.
As already indicated, the present invention can be considered to consist of an artillery missile which is launched in a conventional manner on a ballistic trajectory from a barrel weapon and which, during the launching phase, has the customary outer shape of an artillery shell, but which, after it has passed or in connection with it passing the summit of its ballistic trajectory, extends from its own front part controllable canard fins and folds out or extends at the level of the central part of the missile body fixed main bearing surfaces which, during the launching phase, were curved in against and pressed down in shallow recesses adapted thereto in the outer casing of the missile body, at the same time as stern fins adapted thereto then or previously are extended in the rear part of the missile. The canard fins are then used for guiding the missile on its descending trajectory part at the same time as it has been possible, by virtue of the inclusion of the main bearing surfaces or wings and the stern fins, to combine this possibility of correcting the trajectory of the missile with the fact that it has been possible to impart good gliding characteristics and thus a considerably extended range to the missile during the same trajectory part. The design included in the invention of the extendable main bearing surfaces has been made possible by virtue of the fact that these are made from a resilient material which allows the curving-in which is necessary in order that the main bearing surfaces will be capable of being forced into close contact with the missile body down in the shallow recesses intended therefor and of being locked in this position until the missile is approaching or has just passed the summit of its ballistic trajectory. The material selected for the main bearing surfaces must moreover have such a good inherent shape memory that, after being extended, they adopt the position and any wing profile selected Previously in order to impart the desired gliding characteristics to the missile as a whole. At the same time, the material must have sufficient inherent rigidity in order to be capable of bearing the load which the missile body involves. A main bearing surface or wing of this type can be given the desired wing profile either by means of a bellied plate which is pressed flat in its retracted position or two bellied plates which are welded together with one another along their respective longitudinal edges and are likewise pressed flat in the retracted positions of the bearing surfaces. Materials suitable for this purpose may consist of titanium or titanium alloys.
As far as the stern fins are concerned, these can be designed in a number of different previously known ways and they can be extended at the same time as other bearing surfaces or at a considerably earlier time, for example immediately after the missile leaves the barrel. In the latter case, use is then made of the stern fins for fin-stabilizing the missile already during its ascending trajectory.